minishell

This project is about creating a simple shell - your own little bash - and will give you a lot of experience with processes and file descriptors.

Table of Contents

• Mandatory Part
• Bonus Part

Mandatory part

Program name	minishell
Turn in files	Makefile, *.h, *.c
Makefile	NAME, all, clean, fclean, re
Arguments	N/A
External functs.	readline, rl_clear_history, rl_on_new_line, rl_replace_line, rl_redisplay, add_history, printf, malloc, free, write, access, open, read, close, fork, wait, waitpid, wait3, wait4, signal, sigaction, sigemptyset, sigaddset, kill, exit, getcwd, chdir, stat, lstat, fstat, unlink, execve, dup, dup2, pipe, opendir, readdir, closedir, strerror, perror, isatty, ttyname, ttyslot, ioctl, getenv, tcsetattr, tcgetattr, tgetent, tgetflag, tgetnum, tgetstr, tgoto, tputs
Libft authorized	Yes

Description

Write a shell. Your shell should:

• Display a prompt when waiting for a new command.
• Have a working history.
• Search and launch the right executable (based on the PATH variable or using a relative or an absolute path).
• Not use more than one global variable. Think about it. You will have to explain its purpose.
• Not interpret unclosed quotes or special characters which are not required by the subject such as \ (backslash) or ; (semicolon).
• Handle ' (single quote) which should prevent the shell from interpreting the meta-characters in the quoted sequence.
• Handle " (double quote) which should prevent the shell from interpreting the meta-characters in the quoted sequence except for $ (dollar sign).
• Implement redirections:
  • < should redirect input.
  • > should redirect output.
  • << should be given a delimiter, then read the input until a line containing the delimiter is seen. However, it doesn’t have to update the history!
  • >> should redirect output in append mode.
• Implement pipes (| character). The output of each command in the pipeline is connected to the input of the next command via a pipe.
• Handle environment variables ($ followed by a sequence of characters) which should expand to their values.
• Handle $? which should expand to the exit status of the most recently executed foreground pipeline.
• Handle ctrl-C, ctrl-D and ctrl-\ which should behave like in bash.
• In interactive mode:
  • ctrl-C displays a new prompt on a new line.
  • ctrl-D exits the shell.
  • ctrl-\ does nothing.
• Your shell must implement the following builtins:
  • echo with option -n
  • cd with only a relative or absolute path
  • pwd with no options
  • export with no options
  • unset with no options
  • env with no options or arguments
  • exit with no options

Note: The readline() function can cause memory leaks. You don’t have to fix them. But that doesn’t mean your own code, yes the code you wrote, can have memory leaks